Articular cartilage is a relatively thin tissue located at the ends of articulating bones. Its function is to cushion the mechanical stresses (which hit the bone ends when the bones are moving) to a tolerable level, which does not cause erosion of the cartilage and bone. During ageing, the capacity of the articular cartilage to maintain this function weakens, which may lead to almost complete loss of articular cartilage. This condition named osteoarthritis causes a lot of pain and disability, particularly at ages above 50 years. Articular cartilage has a poor potential to regenerate the cartilage injuries even in younger people caused by, for instance, sports or traffic injuries. Cell-based therapies to repair the cartilage have had suboptimal results with the present-day techniques. In order to develop better therapies it is important to gain better knowledge of the events taking place during the chondrogenesis and osteogenesis. This research aims for that goal.